Efe 2 Task Rapif Fadhila.docx

ACCIDENTAL DISCOVERIES IN TECHNOLOGY Microwave Oven Compiled To Complete The Big Task Of English For Engineering II Course

Compiler

: Rapif Fadhila S (41615310072)

Department

: Industrial Engineering

Semester

: 8th

Lecturer

: Tridata Handayani, ST, MBA,

UNIVERSITAS MERCUBUANA JAKARTA KAMPUS BEKASI 2019

CONTENTS CONTENTS........................................................................................................................................... 2 CHAPTER I ........................................................................................................................................... 3 INTRODUCTION .............................................................................................................................. 3 Chapter II .............................................................................................................................................. 5 2.1 What is Microwave ................................................................................................................. 5 2.2 The Invention Of Microwave Device ................................................................................... 5 2.3 The Invention of Microwave Oven ...................................................................................... 6 2.4 Biography Of Percy Spencer .............................................................................................. 10 2.5 Types Of Microwave Oven .................................................................................................. 12 2.6 How a Microwave Work ....................................................................................................... 13 2.7 The Parts of a Microwave Oven ......................................................................................... 13 2.8 Possitive Effect Of Microwave Use ................................................................................... 15 2.9 Negative Effects Of Microwave Use ................................................................................. 16 Chapter III .......................................................................................................................................... 17 Conclusion ..................................................................................................................................... 17 References ......................................................................................................................................... 19

CHAPTER I

INTRODUCTION Looking at the world we live in today, many things that we have or use are taken for granted. We don't think much about how a telephone works when we're talking to our friends, or how emails and faxes can travel from one unit to another within a blink of an eye. When we go inside our homes and turn on our TV's, do we ever wonder how the human mind could ever comprehend radio waves and electromagnetic energy? How were these things invented? How did anyone get the first ideas to experiment? After all, complex things such as computers, televisions, and microwaves had to have had a great impact on society. And so did simpler things, such as bar codes, plastic, and Velcro.By 1976, over 60% of U.S. households were using microwaves, just 30 years after its first invention. A microwave oven is a kitchen appliance that is in nearly every U.S. home — 90 percent of households have one, according to the U.S. Bureau of Labor Statistics. With the touch of a couple of buttons, this ubiquitous device can boil water, reheat leftovers, pop popcorn or defrost frozen meats in mere minutes. The microwave oven was invented at the end of World War II. Yet it took awhile for them to catch on. At first they were too big and expensive, and people didn't trust them because of the radiation they use. Eventually, technology improved and fears faded. By the 2000s, Americans named the microwave oven as the No. 1 technology that made their lives easier (Sharpe 2017). Today, microwaves are used all around the world, resulting in fresher food, less waste, and money saved. But how did the microwave get started? Who invented them and how did the inventor make such an astounding discovery? Microwaves are a form of electromagnetic radiation that is very similar to sunlight and radio waves but at different frequencies. The term microwave refers to alternating current signals with frequencies between 300 MHz (f=3x108 Hz) to 300 GHz (f = 3x1011 Hz). See figure 1.1 for the location of the microwave frequency band in the

electromagnetic spectrum. The period, T=1/f, of a microwave signal then ranges from 3 ns (3x10-9 s) to 3 ps (3x10-12 s), respectively, and the corresponding electrical wavelength ranges from ʎ= c/f = 1 m to ʎ = 1 mm, respectively, where c = 3x108 m/sec, the speed of light in the outer space or vacuum (Zhang 2017).

Chapter II

2.1 What is Microwave Microwave is fundamentally electromagnetic wave with a wavelength is not too short as visible lights, which is microns or too long as power transmission lines, which is in thousands of miles. Different wavelength gives different perspective of the applications in the real world, which requires a different engineering discipline, even though basic physics is same. For examples, at very low frequency, the major application is power generation, transmission and consumption. Radio frequency (from 535 kHz to 890 MHz) is used for radio broadcast and television. At very high frequency one of the major applications is nuclear engineering. Microwave oven for domestic usage usually has frequency of 2.45 ± 0.025 GHz and industrial microwave processing often uses 915 ± 25 MHz frequency. These two frequencies, called ISM band, are specially allocated to microwave heating applications by FCC. Most of frequency bands are allocated to military communication. Outside of the military uses, some frequency bands for commercial uses are precious treasure of the governments around the world. It can be auctioned at very high price. Your Bluetooth devices use the bandwidth that overlaps with ISM’s. There might be some interference when microwave is operating during your phone conversation if the wireless connection is through Bluetooth technology.

2.2 The Invention Of Microwave Device Wireless

communication

and

microwave

ovens

are

essentially

same

technologies. Nowadays these high-tech devices are integral part of our daily life and we might ask where did this begin? Asking "Who Invented Microwave”, Of course, is like asking who invented electricity. Microwave energy is a natural phenomenon and exists ever since the beginning of the universe. Unlike other natural things, microwaves cannot detected by man’s eyes if not using instrument. People didn’t know this phenomenon for a long time. The discovery really begun with Hans Christian Oersted's famous tests about a wire and a compass. In 1819, Oersted held a wire above a compass. When the current flow through the wire, the compass needle moves. This is one direction from current to

magnetism, later summarized by Ampere's equation. During early 19th century, the most important scientist in electromagnetism was Michael Faraday. Ironically, he was a chemist, but his mutual induction experiments had long lasting impact for modern society, which laid foundation for motor, generator, and transformer. It was Faraday's “lines of force” really intrigued another great physicist, James Clark Maxwell. Maxwell in a sense did not discover anything in the laboratory. But he could think Faraday's experiment in mathematical forms. Not like Faraday, who was a great experimental scientist with not much formal education, Maxwell was born to a Royal Society member family in Scotland and graduated from university by age of nineteen. He created a concept of current potential and proposed 12 equations to unify all the known scientific knowledge of electromagnetism of that time. Scientists in the continental Europe were subscribed on another theory, called “action at distance”. Until 30 years later, 7 years after Maxwell dies (from cancer at age 48) a German engineer, Hertz, in 1885 to 1887 made the historical discovery. His experiments showed, for the first time, the electromagnetic waves could travel through the air without metal conductors. The electromagnetic wave radiator and the receiver were only several meters apart, but that was the beginning of the new era. The discovery of microwave was not by mistakes like many other great discoveries. To authors' best knowledge, it was the first time that a major discovery in physics was led by the results of a self-content mathematical logical system. In a sense, all the practical applications of electromagnetic theory, including radio, TV, radar, communication satellites, wireless phones, originated from the Maxwell’s Equations. The Maxwell’s equations were the unified theory of electric and magnetic laws in precise and neat mathematic formulation

2.3 The Invention of Microwave Oven After the discovery of microwave that can propagate through air in a wireless way, the radar technology was quickly developed and was applied in the detection of enemy aircrafts. Due to the military need, the manufacturing magnetron tube for generation of microwave was exploded during world war 2. Percy Spancer was a selftaught electrical engineer working wireless communication equipment in the navy. He later was working as the leading technologist in the department that manufactured most

of magnetron for the military at Raytheon. The importance of radar technology to wining the war, arguably, is only second to the nuclear bombs. Like many of today's great inventions, the microwave oven was a by-product of another technology. It was during a radar-related research project around 1946 that Dr. Percy Spencer. In 1946, Dr. Percy Spencer noticed something very unusual. As an engineer with the Raytheon Corporation, he was testing a new vacuum tube called a magnetron, (which was also used the previous year in the making of the first electronic computer). During his experimenting, a candy bar in his pocket suddenly began to melt for no apparent reason. This surprised Spencer and sparked an odd curiosity in him. He went off and got some popcorn kernels, bringing them back and laying them in front of the tube. And oddly enough, the popcorn popped all over his lab. Now the experimenting began.The next morning, Spencer and a curious colleague of his got to together to continue searching out the cause of the previous happenings. They placed an egg by the tube, which eventually began to tremor and quake. The rapid temperature rise within the egg was causing tremendous internal pressure. Evidently the curious colleague moved in for a closer look just as the egg exploded and splattered hot yolk all over his amazed face. The face of Spencer lit up with a logical scientific conclusion: the melted candy bar, the popcorn, and now the exploding egg, were all attributable to exposure to low-density microwave energy. Thus, if an egg can be cooked that quickly, why not other foods? Experimentation began. Dr. Spencer fashioned a metal box with an opening into which he fed microwave power. The energy entering the box was unable to escape, thereby creating a higher density electromagnetic field. When food was placed in the box and microwave energy fed in, the temperature of the food rose very rapidly. Dr. Spencer had invented what was to revolutionize cooking, and form the basis of a multimillion dollar industry, the microwave oven. Spencer and other researchers at the company spent the next few months developing what was to become the first microwave oven. Raytheon unveiled the

appliance—called the Radarange because the magnetron is the source of microwaves in a radar set—the following year. Later in 1946, Raytheon filed for a patent for a microwave oven that could cook food. Marvin Bock, an engineer at the company, built an appliance that would become the Radarange. It relied on an output power of 1.6 kW from a water-cooled, permanentmagnet magnetron. A prototype, which was almost 2 meters tall and weighed about 340 kilograms, was installed in a Boston restaurant for testing. The first commercial microwave oven was tested in a Boston restaurant in 1947. Later that year, Raytheon introduced the Radarange 1161. It stood 5.5 feet (1.7 meters) tall, weighed 750 lbs. (340 kilograms) and cost $5,000, according to Gallawa. It sold for about US $5,000 (equivalent to approximately $64,000 today) and was marketed to commercial kitchens. It took more than 25 years for the appliance to become small enough and affordable enough to be a household staple. Despite some safety concerns, by the mid-1970s millions of microwave ovens were being sold to consumers each year. In 1955 Raytheon marketed a slightly smaller 220-volt wall unit for the home, at a price of $1,295 (about $11,440 today). It did not sell well. Sharp developed the R-10, Japan's first microwave oven in 1961. The following year, Sharp became the first company to mass produce microwave ovens. Raytheon in 1965 acquired Amana, an appliance company in Newton, Iowa. In 1967, the first Amana home microwave oven, a 110-volt countertop model, sold for $495 (about $3,515 today). It was some 40 centimeters tall, 50 cm wide, and 30 cm deep. This popular version paved the way for the smaller, cheaper microwave ovens in use today. It had to be hooked up to a water line because the magnetron was water-cooled. It took a few years for the public to overcome their initial reluctance but as technology improved, microwave ovens grew in popularity, particularly in the food industry. Restaurants could keep cooked recipes in the refrigerator and heat them to order reducing waste. Other food industry establishments used microwaves for roasting coffee beans and peanuts, defrosting and precooking meat, and even shucking oysters.

The microwave oven had reached a new level of acceptance, particularly with regard to certain industrial applications. By having a microwave oven available, restaurants and vending companies could now keep products refrigerator-fresh up to the point of service, then heat to order. The result? Fresher food, less waste, and money saved. Soon after, microwave ovens became more popular than even the dishwasher due to decreasing sizes and costs. In 1975, only 4 percent of U.S. homes had a microwave oven, according to Gallawa; in 1976, the number jumped to 14 percent. Today, approximately 90 percent of households in the United States have a microwave oven, according to the Bureau of Labor Statistics. An expanding market has produced a style to suit every taste; a size, shape, and color to fit any kitchen, and a price to please almost every pocketbook. Options and features, such as the addition of convection heat, probe and sensor cooking, meet the needs of virtually every cooking, heating or drying application. Today, the magic of microwave cooking has radiated around the globe, becoming an international phenomenon.

2.4 Biography Of Percy Spencer Full name :Percy LeBaron Spencer Born: 19-Jul-1894 Birthplace: Howland, ME Died: 8-Sep-1970 Cause of death: unspecified Gender: Male Race or Ethnicity: White Sexual orientation: Straight Wife: Louise Spencer (three sons) Son: George Spencer

Son: James Spencer Son: John Spencer Occupation: Scientist, Inventor Nationality: United States Executive summary: Invented the microwave oven Military service: US Navy (1912-18)

Spencer was born in 1894 in Howland, Maine. He dropped out of grammar school at age 12 to work as a spindle boy in a weaving mill, but in his early years he taught himself about electricity, even setting up a new electrical system at a local paper mill. When he was 18, Spencer joined the U.S. Navy as a radio operator. During this time he taught himself a number of scientific subjects, including calculus, chemistry, metallurgy, physics, and trigonometry. Spencer later remembered, “I just got hold of a lot of textbooks and taught myself while I was standing watch at night.” Percy Spencer's father died when he was an infant, and his mother soon abandoned the family. He was raised by an impoverished aunt and uncle, and had little formal schooling. In his teens he was intrigued by the burgeoning use of electric power and worked as an electric installer, wiring businesses with power. He then joined the Navy, where he was sent to radio school, and after being discharged he worked for Wireless Specialty Apparatus Company, a major manufacturer of commercial and military radio equipment that was eventually absorbed into RCA. He joined Raytheon in the 1920s, and quickly became the company's expert on tube design. During World War II he oversaw the company's exponential increase in manufacturing tubes for military applications, and the mass production of magnetrons (which power radar equipment), which proved of immeasurable value to allied forces in winning that war. An auto-didact, Spencer held more than 300 patents,

After World War I, Spencer joined the American Appliance Company in Cambridge, MA, which would later become the Raytheon Company. During World War II, Raytheon was contracted by the British to mass produce their newest invention: combat radar equipment. In desparate need of radar to detect German planes and submarines, the British turned to the United States to produce the cavity magnetron, radar's primary component. Spencer developed a system of mass production for the magnetron, increasing its production output to 2600 per day. With radar becoming increasingly commonplace, the head of Electronics at the U.S. Navy's Bureau of Ships, Commodore Jennings Dow, asserted, "Raytheon radar had a marked effect on every major sea engagement of the war." For his work during the war, Spencer received the Distinguished Public Service Award from the U.S. Navy, its highest civilian honor.

Spencer is best known as the inventor of the microwave oven. During his research into electromagnetic waves in the 1940s, Spencer noticed that a candy bar in his pocket melted when he was standing next to a magnetron. He realized that electromagnetic waves could be used to cook food, and Spencer subsequently filed a patent with Raytheon for the RadarRange in 1945 (FamousInventors.org 2019). As Vannevar Bush once said, Spencer “earned the respect of every physicist in the country, not only for his ingenuity, but for what he has learned about physics by absorbing it through his skin.”

2.5 Types Of Microwave Oven In the market there are several types of microwave ovens, the distribution of the type of microwave oven is based on the size of the microwave. The classification can be mentioned as follows: 1. Compact Microwave Compact microwaves are also called portable microwaves, which are the smallest types of microwave ovens. The size of this type of oven is about 46 cm in width, 35 cm in thickness and 30 cm in height. The power used to operate this type of oven is between 500 to 1000 watts. The price of this type of microwave oven is less than $ 100 US.

2. Medium Capacity Microwave This type of microwave has a larger size than compact microwave. For the electricity needed to operate this type of oven around 1000-1500 watts. This type of microwave has the ability to cook and warm food faster than compact microwaves.

3. Large Capacity Microwave This type of oven is the largest type with a size larger than the microwave medium. The electricity needed to operate this type of oven reaches 2000 watts. Large microwaves are suitable for restaurants or places that require large amounts of food.

2.6 How a Microwave Work First of all, we need to know exactly how microwave ovens work. Microwave ovens function on high frequency electromagnetic waves. These high frequency waves work by causing a vibrating motion on the water molecules that are naturally present in all food. When the water molecules vibrate, it causes a friction, which causes the temperature in the food to rise, thus making it warmer, and either thawing or cooking the raw materials. And microwaving cooks the food much faster than regular cook tops, because microwaves begin the process from within the food, and warms the food up to its outermost layer. This is the opposite of how cook tops work; going from the outermost layer to the innermost takes much longer than the other way around.

2.7 The Parts of a Microwave Oven The Two Major Systems in the Microwave Two separate but connected systems comprise the microwave's inner workings: The control section and the high-voltage section. The control section channels electricity safely from the source to the microwave itself. The high-voltage section, then, does the actual work by converting that electricity into microwave rays and emitting them into the main chamber to warm up or cook the food. Additionally, both the control and highvoltage sections may include sensors or other security devices to prohibit overheating or any other dangerous malfunction that can pose a safety hazard.

Triac Part of the microwave oven's control system, the triac is a device that helps channel the electricity from the source – for example, from the outlet through the cord – to the high-voltage system. By default, this electromechanical relay seals the circuits of the microwave off from the electricity that flows through the outlet and the oven's plugged-in cord. However, when the microwave is turned on, sensors indicate that all the devices are working and ready to produce microwave energy to heat up your food or liquid. When these conditions are met, the triac then switches into an "on" position. This permits the electrical current to flow to the high voltage transformer. High Voltage Transformer The high voltage transformer solves a very specific problem. Unique among household appliances, a microwave oven actually requires more power than the normal voltage that your home's electrical wiring produces. In order to solve this issue, the microwave oven uses a very specific device called the high voltage transformer. The transformer's function is to magnify the power available to the oven from the home's wiring to the level necessary to produce microwaves. Essentially, the high voltage transformer is a series of capacitors. These capacitors loop the flowing electrical current to make it much more powerful – usually around 3000 volts from the normal 115 volts of household electricity in the United States.

Magnetron Tube When the electricity's voltage has been amplified sufficiently, it's then passed on to the magnetron tube. This is the part of the microwave oven that converts the electrical current into microwave energy. This specially-made diode uses magnetic fields to control electrons. As the electrons pass through the diode, they heat up a filament, thus causing electrons to split off in the form of microwave energy.

Wave Guide Once the microwave energy is created, a device called the wave guide then channels and directs the microwaves into the cooking chamber. The microwaves then bounce off the inner walls of the oven while passing through the food or drink on the turntable or platform. The Cooking Cavity and the Frame The microwave energy produced by microwave ovens can be quite dangerous to humans. That's why microwave ovens utilize a deep cavity for cooking – any substance you want to heat or cook is placed inside this cavity. (Sisk 2018)

2.8 Possitive Effect Of Microwave Use 

Cooks much faster

First of all, as mentioned before, the time taken to cook or reheat food in a microwave is much shorter than it would take on a stove top or a cook top. And in this day of extreme busyness for every person, time is certainly of essence. Every person has to cook for themselves and maybe even for a family, and probably have to multitask getting themselves and everyone else in the family- maybe children as well- ready for the day. When you use a microwave oven, it becomes much easier to cook food quickly. You can also save time by cooking in batches and simply reheating the food in the morning or at the time of the meal.



Very convenient And it is not just about the time; microwaves are truly convenient for modern life.

You have to carry your food to your workplace in regular lunchboxes, unless you can afford the rather expensive self heating boxes. By the time you sit down to eat your lunch, the food would be quite cold and unappetizing. If you have a microwave at your workplace, all you have to do is pop your microwave friendly lunchbox in, set the time and temperature, and treat yourself to a nice, hot lunch. Yes, this could be done with a

stove top or a cook top as well, but that would take much longer, not to mention that you would need to carry an extra bowl for reheating the food; no plastic has been commercially known to stand the heat of fire or a heated glass surface of an induction cook top.

2.9 Negative Effects Of Microwave Use  Might lead to accidents

The biggest problem, of course, is the chance of accidents. Microwaves have been known to become overheated and burst, or succumbing to a technical failure that can lead to short circuits and serious electrical fires. In some cases, heating liquids in a microwave can lead to an unfortunate accident; unlike in regular cooking methods, the liquid in a microwave does not boil, and hence it looks deceptively cold. Handling such liquids can lead to quite severe burns.  Might release chemicals Leching is yet another problem with microwaves.

Sometimes, the heating

process causes chemicals to seep into the food, thanks to the microwave friendly containers, some of which contain harmful chemicals. Some studies suggest that these chemicals might be carcinogenic (Effects 2019).

Chapter III Conclusion A longstanding and peculiar myth about microwave ovens, that microwaves cook food from the inside out, got started at the very beginning of the microwave oven industry. It was based on the observations of Dr. Percy L. Spencerof the Raytheon Corporation. The company had worked on Radar during World War II, but in 1946, Spencer, more or less by accident, hit on the idea of cooking food with microwave energy. He had been testing a magnetron, which is the device that emits the microwaves. Taking a snack break, he noticed a chocolate bar in his pocket had melted, even though the day was cool. Thinking that maybe it had to do with the magnetron, he aimed it at some popcorn kernels. They popped. Then he tried a raw egg. It exploded. Why did the egg explode? Steam pressure built up within its shell. If steam pressure could build up within the confined shell of an egg so quickly that it exploded, what does this mean? It must mean that the microwaves are cooking the inside part first.

References Effects, P. N. (2019). " Positive And Negative Effects Of Microwave Use." Retrieved 28, 2019, from http://www.positivenegativeeffects.com/microwave. FamousInventors.org. (2019). "Percy Spencer." Retrieved March 26, 2019, from https://www.famousinventors.org/percy-spencer. Sharpe, E. (2017). "Microwave Oven." Retrieved March 26, 2019, from http://www.smecc.org/microwave_oven.htm. Sisk, A. (2018). "The Parts of a Microwave Oven." Retrieved March 25, 2019, from https://www.hunker.com/13407974/the-parts-of-a-microwave-oven. Zhang, H. (2017). "The History of Microwave Heating." Research Gate Publication.